Bio-diesel is a diesel replacement fuel that is manufactured from vegetable oils, recycled cooking greases or oils, or animal fats. Numerous studies have shown that most exhaust emissions encountered with conventional diesel fuel are reduced with bio-diesel, with the exception of nitrogen oxide emission. In fact, some of the conducted research shows an increase of nitrogen oxide emission by about 10% to 13% in bio-diesel used as compared to petrol diesel. In order to reduce the nitrogen oxide emission from the bio-diesel combustion, modification of the engine combustion chamber and post-exhaust treatment installation are applicable techniques. Alternatively, the reduction of nitrogen oxide emission can be achieved by using an improved fuel composition. The improved fuel composition may contain additives to attain the desired object.
U.S. Patent Publication No. 20050060928, disclosed a fuel composition comprising an emulsion of bio-diesel and alkoxylated alcohol as well as alkoxylated fatty acid with the aid of alkanolamide. In this U.S. application, the fuel composition is only constituted of low amounts of bio-diesel while other component of the fuel composition derives from the surfactant mixture.